Avalanche Advisory

Turnagain Area Avalanche Advisory

Sunday, April 5th 2015 6:16 am by Wendy Wagner

ARCHIVED ADVISORY - All advisories expire after 24 hours from the posting date/time.

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The Bottom Line

The avalanche danger is MODERATE above 2,000' on Northerly aspects for triggering a slab avalanche 2-3' thick. The likelihood for triggering one of these large slides on steep shady slopes is decreasing, but the consequences remain high. Other areas of concern are fresh wind slabs and loose snow avalanches where up to 6" of storm snow accumulates today as well as large and overhanging cornices.

Show the Complete North American Avalanche Danger Scale

North American Public Avalanche Danger Scale

Avalanche danger is determined by the likelihood, size and distribution of avalanches.

Danger Level

Travel Advice

Likelihood of Avalanches

Avalanche Size and Distribution

5 Extreme

Avoid all avalanche terrain.

Natural and human- triggered avalanches certain.

Large to very large avalanches in many areas.

4 High

Very dangerous avalanche conditions. Travel in avalanche terrain not recommended.

Natural avalanches likely; human- triggered avalanches very likely.

Large avalanches in many areas; or very large avalanches in specific areas.

Although a storm is slowly rolling in today for the early part of the week, we are still concerned about weak snow sitting under a 2-3' slab on Northerly aspects. For the past 5 days we have been investigating a number of buried weak layers that were highly reactive Tuesday through Friday and over the weekend have shown signs of gaining strength. Despite the decreasing possibility of triggering a slab, good travel habits are important to stick to if venturing into the soft snow on Northerly slopes. This means exposing one person at a time, watching your partners, having escape routes planned if the snow moves and have all your rescue gear in working order and know how to use it.

Avalanche Problem 2

Fresh shallow wind slabs and loose snow avalanches may be found today with an expected 2-6" of new snow. Ridgetop winds are forecast to be just strong enough to move the new snow around and build soft slabs anywhere from 4-8" thick. These are not likely to pack much of a punch unless more snow and/or wind develops. In some areas they will be forming on a slick crust and if you find a larger 8" pocket, say, it could run further than expected.

Sluffs in the new snow should be expected on steep slopes (where enough snow accumulates). If steep South slopes warm later in the day, natural wet/damp sluffs will be likely, yet low volume.

Additional Concern

Cornices will continue to deserve respect from now until they are melted out or calved off. It's also important to remember that daytime heating can weaken their roots and increase the likelihood for collapse, natural or human triggered.

Check out the photo from Friday below, yikes. Sadly, Alaska had its third avalanche fatality last week when a cornice broke taking a skier with it. This happened in the Wrangell-St Elias area and while details are currently being gathered, you can see the preliminary write up along with the Nation's other fatalities HERE.

"Things not appearing as they seem" and "Don't follow our tracks!" were the quotes referring to the photo. This was sent in to us from two longtime supporters of the CNFAIC that were skiing the North ridge of Eddies Bowl. See their write up HERE.

Mountain Weather

Yesterday's impending sunny and warm day was cut short with clouds and a cool breeze moving in by the afternoon. High temperatures were around 30F on the ridgetops and 45F at 1,000'. Ridgetop winds were from the East in the 5-15mph range.

Overnight, precipitation has started up in some areas associated with a large low-pressure system in the Bering. This is pushing a warm front in from the Southwest and up Cook inlet (a good set-up for precipitation in Anchorage). Although Turnagain Pass is still dry this morning, the Alyeska Mid station (1,700') has picked up 3" of new snow! We should see an additional 2-4" of snow through the day. Winds will be light to moderate from the South and East, 10-15mph. Temperatures in the mid-20's F on the ridgelines and low 30's F at 1,000'. We should see snow to, or very close to, sea level.

Monday and Tuesday the bulk of the precipitation and stormy weather is expected to hit us. Temperatures look to warm enough for rain as high as 1,000', possibly higher, and precipitation amounts are in the .5-1" of water range by Tuesday evening. Stay tuned.

PRECIPITATION 24-hour data (6am - 6am)

Temp Avg (F)

Snow (in)

Water (in)

Snow Depth (in)

Center Ridge (1880')

34

0

0

58

Summit Lake (1400')

33

0

0

10

Alyeska Mid (1700')

35

3

0.25

33

RIDGETOP 24-hour data (6am - 6am)

Temp Avg (F)

Wind Dir

Wind Avg (mph)

Wind Gust (mph)

Sunburst (3812')

25

E

9

26

Seattle Ridge(2400')

27

n/a

10

35

This is a general backcountry avalanche advisory issued for Turnagain Arm with Turnagain Pass as the core advisory area (this advisory does not apply to highways, railroads, or operating ski areas).

Riding status is not associated with avalanche danger. An area will be open to motorized use in accordance to the Forest Management Plan when snow coverage is adequate to protect underlying vegetation. Backcountry hazards including avalanche hazard are always present regardless of the open status of motorized use areas.

(Updated: Dec 18, 2018 )

AREA

STATUS

WEATHER AND RIDING CONDITIONS

Glacier District

Johnson Pass:

Open

Please stay on trail to avoid resource damage through Forested areas.

Placer River:

Closed

Closed

Skookum Drainage:

Closed

Closed

Turnagain Pass:

Closed

Closed November 21 due to inadequate snow conditions. #hopeforsnow

Twentymile:

Closed

Closed

Seward District

Carter Lake:

Open

Lost Lake Trail:

Open

Please stay on trail to avoid resource damage through Forested areas.

Primrose Trail:

Open

Please stay on trail to avoid resource damage through Forested areas.

Resurrection Pass Trail:

Closed

Closed for the 2018/19 season. Next season will be open to motorized use.

The information in this advisory is from the U.S. Forest Service, which is solely responsible for its content. This advisory describes general avalanche conditions and local variations always occur.
This advisory provided by the Chugach National Forest, in partnership with Friends of the Chugach National Forest Avalanche Information Center.